[Study on the Structure and Nanomechanical Properties of Organic Montmorillonite Reinforced Urea-Formaldehyde Adhesive].

Montmorillonite (MMT) is a natural mineral that has great potential as reinforcing filler in wood adhesives. In order to study the reinforcing mechanism more clearly, organic MMT-reinforced urea-formaldehyde adhesive (UF-OMMT) was prepared to analyze its chemical properties and crystal structure with Fourier Transform Infrared Spectroscopy (FTIR) and X-Ray Diffraction (XRD). The nanomechanical properties of UF, UF-MMT and PF-OMMT adhesives in the interphase of wood-based composite were analyzed by nanoindentation (NI) and the macro-bonding strength of composite were also tested.

[Fine root biomass and its nutrient storage in karst ecosystems under different vegetations in Central Guizhou, China].

The degeneration of karst ecosystem is closely associated with the reduction of soil nutrients and fine root biomass, and the retention of soil nutrients is of significance in sustaining ecosystem functioning. To understand the changes in the fine root biomass and soil nutrient retention in degenerated karst ecosystems, a comparative study was conducted with three typical vegetation stands (forest, shrub, and shrub-grass) in Central Guizhou of Southwest China. Soil samples with fine roots were collected from the depths 0-5 cm, 5-10 cm, and 10-15 cm, with the related indices of fine roots and nutrients measured.